Copyright (c) by W. H. Freeman and Company Chapter 18 Cell Motility and Shape I: Microfilaments

Copyright (c) by W. H. Freeman and Company 18.1 The actin cytoskeleton  Actin filaments (or microfilaments) are one of the three protein filament systems that comprise the cytoskeleton  Eukaryotic cells contain abundant amounts of highly conserved actin Figure 18-1

Copyright (c) by W. H. Freeman and Company 18.1 ATP holds together the two lobes of the actin monomer Figure 18-2a

Copyright (c) by W. H. Freeman and Company 18.1 G-actin assembles into long, helical F-actin polymers Figure 18-2b,c

Copyright (c) by W. H. Freeman and Company 18.1 The actin cytoskeleton is organized into bundles and networks of filaments Figure 18-4

Copyright (c) by W. H. Freeman and Company 18.1 Actin cross-linking proteins bridge actin filaments to form bundles and networks Figure 18-5

Copyright (c) by W. H. Freeman and Company 18.1 Cortical actin networks are connected to the plasma membrane: erythrocytes Figure 18-7

Copyright (c) by W. H. Freeman and Company 18.1 During blood clotting, platelets change shape due to changes in the actin cytoskeleton Figure 18-8

Copyright (c) by W. H. Freeman and Company 18.1 Cross-linkage of actin filament networks to the plasma membrane in various cells Figure 18-9

Copyright (c) by W. H. Freeman and Company 18.1 Actin bundles support projecting fingers of membrane Figure 18-10

Copyright (c) by W. H. Freeman and Company 18.2 Actin polymerization in vitro proceeds in three steps Figure Animação

Copyright (c) by W. H. Freeman and Company 18.2 Actin filaments grow faster at one end that at the other Figure Several toxins can disrupt the actin monomer-polymer equilibrium

Copyright (c) by W. H. Freeman and Company 18.2 Actin polymerization is regulated by proteins that bind G-actin Figure 18-15a,b

Copyright (c) by W. H. Freeman and Company 18.2 Many movements are driven by actin polymerization The acrosome reaction in echinoderm sperm Figure 18-17

Copyright (c) by W. H. Freeman and Company 18.2 Movement of intracellular bacteria and viruses depends on actin polymerization Figure 18-18

Copyright (c) by W. H. Freeman and Company 18.2 Actin polymerization at the leading edge of moving cells Figure Actin Dinamics in moving cells Actin in Lamelipodia Movements

Copyright (c) by W. H. Freeman and Company 18.3 Myosin: the actin motor protein All myosins have head, neck, and tail domains with distinct functions Figure 18-20

Copyright (c) by W. H. Freeman and Company 18.3 Functions of the myosin tail domain Figure 18-21

Copyright (c) by W. H. Freeman and Company 18.3 Myosin heads walk along actin filaments Figure animação

Copyright (c) by W. H. Freeman and Company 18.3 Myosin and kinesin share the Ras fold with certain signaling proteins Figure 18-24

Copyright (c) by W. H. Freeman and Company 18.3 Conformational changes in the myosin head couple ATP hydrolysis to movement Figure animação

Copyright (c) by W. H. Freeman and Company 18.4 Muscle: a specialized contractile machine Figure 18-26

Copyright (c) by W. H. Freeman and Company 18.4 Skeletal muscle contains a regular array of actin and myosin Figure 18-27

Copyright (c) by W. H. Freeman and Company 18.4 Capping proteins stabilize the ends of actin thin filaments in the sarcomere Figure 18-28

Copyright (c) by W. H. Freeman and Company 18.4 Thick and thin filaments slide past one another during contraction Figure 18-29

Copyright (c) by W. H. Freeman and Company 18.4 Titin and nebulin filaments organize the sarcomere Figure 18-30

Copyright (c) by W. H. Freeman and Company 18.4 A rise in cytosolic Ca 2+ triggers muscle contraction (part I) Figure 18-31a

Copyright (c) by W. H. Freeman and Company 18.4 A rise in cytosolic Ca 2+ triggers muscle contraction (part II) Figure 18-31b

Copyright (c) by W. H. Freeman and Company 18.4 Tropomyosin and troponin regulate contraction in skeletal muscle Figure 18-32

Copyright (c) by W. H. Freeman and Company 18.4 Ca 2+ -dependent mechanisms for regulating contraction in skeletal and smooth muscle Figure 18-33

Copyright (c) by W. H. Freeman and Company 18.4 Myosin-dependent mechanisms also control contraction in some muscles Figure 18-34

Copyright (c) by W. H. Freeman and Company 18.5 Actin and myosin II are arranged in contractile bundles that function in cell adhesion Figure 18-35

Copyright (c) by W. H. Freeman and Company 18.5 Myosin II stiffens cortical membranes Figure 18-36

Copyright (c) by W. H. Freeman and Company 18.5 Actin and myosin II have essential roles in cytokinesis Figure 18-37

Copyright (c) by W. H. Freeman and Company 18.6 Controlled polymerization and rearrangements of actin filaments occur during keratinocyte movement Figure Video Animação

Copyright (c) by W. H. Freeman and Company 18.6 A model of the molecular events at the leading edge of a moving cell Figure 18-42

Copyright (c) by W. H. Freeman and Company 18.6 Myosin I and myosin II have important roles in cell migration Figure 18-43

Copyright (c) by W. H. Freeman and Company 18.6 Changes in localization of cytosolic Ca 2+ during cell location Figure 18-45

Copyright (c) by W. H. Freeman and Company Chapter 19 Cell Motility and Shape II: Microtubules and Intermediate Filaments

Copyright (c) by W. H. Freeman and Company 19.1 Heterodimeric tubulin subunits compose the wall of a microtubule Figure 19-1

Copyright (c) by W. H. Freeman and Company 19.1 Heterodimeric tubulin subunits compose the wall of a microtubule Figure 19-2

Copyright (c) by W. H. Freeman and Company 19.1 Arrangement of protofilaments in singlet, doublet, and triplet microtubules Figure 19-3

Copyright (c) by W. H. Freeman and Company 19.1 Microtubules form a diverse array of both permanent and transient structures Figure 19-4 Microtubule networks

Copyright (c) by W. H. Freeman and Company 19.1 Microtubules assemble from organizing centers Figure 19-5

Copyright (c) by W. H. Freeman and Company 19.1 The  -tubulin ring complex nucleates polymerization of tubulin subunits Figure 19-8

Copyright (c) by W. H. Freeman and Company 19.2 The steps of microtubule assembly Figure 19-11

Copyright (c) by W. H. Freeman and Company 19.2 The ends of growing and shortening microtubules appear different Figure 19-12

Copyright (c) by W. H. Freeman and Company 19.2 Dynamic instability is an intrinsic property of microtubules Figure 19-13

Copyright (c) by W. H. Freeman and Company 19.2 Dynamic instability in vivo Figure 19-14

Copyright (c) by W. H. Freeman and Company 19.2 The GTP cap model has been proposed to explain dynamic instability Figure 19-15

Copyright (c) by W. H. Freeman and Company 19.2 Assembly MAPs co-localize with microtubules in vivo Figure MicrotubulesMAP4 MAP=Microtubule associated proteins

Copyright (c) by W. H. Freeman and Company 19.3 Different proteins are transported at different rates along axons Figure 19-19

Copyright (c) by W. H. Freeman and Company 19.3 Fast axonal transport occurs along microtubules Figure 19-20

Copyright (c) by W. H. Freeman and Company 19.3 Intracellular vesicles and some organelles travel along microtubules Figure ER Microtubules

Copyright (c) by W. H. Freeman and Company 19.3 The structure of the kinesin microtubule motor protein Figure 19-23

Copyright (c) by W. H. Freeman and Company 19.3 Kinesin is a (+) end-directed motor Figure 19-24

Copyright (c) by W. H. Freeman and Company 19.3 Microtubule motors: kinesins and dyneins

Copyright (c) by W. H. Freeman and Company 19.3 Dynein-associated MBPs tether cargo to microtubules Figure 19-25

Copyright (c) by W. H. Freeman and Company 19.3 Multiple motor proteins are associated with membrane vesicles Figure 19-26

Copyright (c) by W. H. Freeman and Company 19.4 Cilia and flagella: structure and movement Figure 19-27

Copyright (c) by W. H. Freeman and Company 19.4 All eukaryotic cilia and flagella contain bundles of doublet microtubules Figure 19-28

Copyright (c) by W. H. Freeman and Company 19.4 Axonemes are connected to basal bodies Figure 19-29

Copyright (c) by W. H. Freeman and Company 19.4 Ciliary and flagellar beating are produced by controlled sliding of outer doublet microtubules Figure 19-30

Copyright (c) by W. H. Freeman and Company 19.4 Dynein arms generate the sliding forces in axonemes Figure 19-31

Copyright (c) by W. H. Freeman and Company 19.4 Axonemal dyneins are multiheaded motor proteins Figure 19-32

Copyright (c) by W. H. Freeman and Company 19.5 The stages of mitosis and cytokinesis in an animal cell Figure Movimento dos cromossomas

Copyright (c) by W. H. Freeman and Company 19.6 Functions and structure of intermediate filaments distinguish them from other cytoskeletal fibers Figure 19-50

Copyright (c) by W. H. Freeman and Company 19.6 All IF proteins have a conserved core domain and are organized similarly into filaments Figure 19-51

Copyright (c) by W. H. Freeman and Company 19.6 A purified neurofilament Figure 19-52

Copyright (c) by W. H. Freeman and Company 19.6 Intermediate filaments are dynamic polymers in the cell Figure 19-53

Copyright (c) by W. H. Freeman and Company 19.6 Various proteins cross-link intermediate filaments and connect them to other cell structures Figure 19-54

Copyright (c) by W. H. Freeman and Company 19.6 Intermediate filaments are anchored in cell junctions Figure 19-56

Copyright (c) by W. H. Freeman and Company 19.6 Desmin and associated proteins stabilize sarcomeres in muscle Figure 19-57